Scavenging-air valve for soot blowers



Jan. 18, 1955 R H WAGER 2,699,799

SCAVENGING-AIR VALVE FOR SOOT BLOWERS Filed Oct. 4, 1949 2 Sheets-Sheet`2 /0 ETCEE- I N VEN TOR 3y iEBKDABEfe-rfi:17V/176.15,

ATTORNEYS United States Patent O SCAVENGlNG-AIR VALVE FOR SOOT BLWERSRobert Hudson Wager, South Orange, N. J. Appiication October 4, 1949,Serial No. 119,416 Claims. (Cl. 137-498) My invention relates to valveswhich are spring-opened to permit the passage of air or other fluid at alow pres sure but which are automatically closed when a fluid of muchhigher pressure is applied to the discharge side of the valve. Moreparticularly the invention relates to valves of this character which areused to admit scavenging air to the heads of soot blowers of the fluidjet type when the blowers are not in use, but which may be used forother purposes where an automatic spring check valve for high and lowpressure may be necessary.

The soot and dust which accumulates on the water tubes of steam boilerfurnaces and the like are periodically removed by soot blowers usuallyof the steam jet type. Such a blower usually comprises a head supportedon the boiler and connected to receive high pressure steam therefrom.Within the head is a valve which controls the admission of the steam tothe blower element, the latter being a long pipe with many jet nozzlesfor directing jets of stam against the water tubes to be cleaned. Theblower element is mounted for rotation so that the jets or blasts sweepover a bank of tubes to blow the soot therefrom,

' and the steam valve is operated in timed relation to the rotation ofthe element. When the blower is not being used the furnace gasescontaining sulphur and other corrosive ingredients, work back throughthe blower element into the head and cause considerable corrosion. lt isnow common practice to admit scavenging air into the blower heads whenthey are not in use, and thus prevent the entrance of such corrosivegases. The scavenging air comes from the forced draft fans at the top ofthe boiler at a pressure of about onehalf to one pound or more persquare inch and through a supply pipe connected to the head beyond theseat of the steam inlet valve. Since the steam pressure varies fromabout one hundred pounds up to about six hundred pounds per square inch,it has been a problem to provide between the air supply pipe and theblower head an automatic valve which would close and seal the lowpressure air line when the high pressure steam is admitted to theelement during the blowing operation and which would open to permit thelow pressure scavenging air to low through the element f when the steamcontrol valve is closed.

The primary object of my invention is to provide a valve of thischaracter which will function effectively under such wide variations ofpressures and which will be reliable and durable in use over a longperiod of time.

Another object is to provide in a device of this character improvedmeans for preventing the valve and its seat from being injured whensteam at a high pressure is admitted.

A further object is to provide means which will permit the same valvestructure to be used eiective in connection with both low and highpressure boilers or the like.

Further objects and advantages will be apparent from the followingdescription of the present preferred embodiments of the invention inconnection with the accompanying drawings in which,

Fig. 1 is a vertical transverse sectional view through the head of asoot blower showing the application of the valve thereto,

Fig. 2 is a longitudinal section through the valve on an enlarged scaletaken on the line 2-2 of Fig. 1 looking in the direction of the arrows,

Iig. 3 is a side elevation of the valve on an enlarged sca e,

Fig. 4 is a side view of the movable valve member,

Fig. 5 is an end view of the member shownin Fig. 4,'

Fig. 6 is a perspective View of a ring usable on the movable valvemember when the valve is used in connection with low boiler pressures,

Fig. 7 is a longitudinal section through a modified form of the valve,and

Fig. 8 is a cross section of the modified valve on the line 8 8 of Fig.7.

Referring more in detail to the drawings, Fig. 1 shows a side view of myimproved valve, generally indicated by the numeral 1G, applied to oneside of the hollow body 11 of a soot blower head 12 of a well knowntype, the valve having a scavenging air supply pipe 13 coupled to itsouter end. The body 11 is shown as having on opposite sides bosses 14with threaded bores so that the valve may be connected to either boss,the other boss being plugged. The rotatable blower element (not shown)is operatively connected to the head and steam is periodically admittedto it through a control valve, the steam entering the head through aninlet portion 15. The valve is of course positioned on the boiler sideof the steam valve of the blower.

The valve 10 comprises a two-piece body or casing within which is thevalve proper and a coil spring for moving the latter in a direction awayfrom its seat. The casing consists of an elongated body portion 16 and aremovable cap or attaching portion 1'7. These two sections or parts arepreferably made of Monel metal and have hexagonal exterior surfaces asseen in Figs. 1 and 3 for engagement by a wrench. The outer or lowpressure inlet end of the body 16 is reduced and internally screwthreaded as at 18 to facilitate the connection of the air supply pipe13. The inner end of the body 16 is also internally threaded at 19 toreceive a reduced and threaded portion 20 at one end of the cap orbonnet 17. A threaded attaching neck 21 is formed on the other end ofthe cap or cover for engagement with a threaded openr ing 22 in the body11 of the blower. A suitable gasket or sealing ring 23 is placed betweenthe abutting portions of the body and cap as shown in Fig. 2.

The bore or passage through the valve body 16 has a major cylindricalvalve chamber portion 24 in which the threads 19 are formed and asmaller portion 25 in which the threads 18 are formed. Between theseportions is formed a beveled annular valve seat 26 for a valve 27 of thedisk or poppet type. A guiding stem 28 is formed integral with the valvehead or member 27 and has a cylindrical piston-like end portion with asliding tit in an enlarged chamber-like portion 29 of the bore 30through the cap 17. There is preferably a clearance of ten thousandthsof an inch between the parts 28 and 29 so that the valve will beaccurately guided toward and from its seat 26. The stem of the valve isformed between the head 27 and the end 28 with a portion 31 of reduceddiameter; and between the portions 28 and 31 is an annular disk-likecollar 32 having a diameter slightly less than the valve chamber or bore24. This cylindrical collar 32 has a free sliding t in the valvechamber. A coiled compression spring 33 surrounds the valve head andstem portion 31, thrusting at one end against an annular shoulder 34 atthe end of the bore 24 and one side face of the collar or iiange 32, asseen in Fig. 2. The spring biases the valve to its open position shownin Fig, 2 and normally holds the other `face of the collar against theadjacent reduced end 20 of the cap or cover. The collar thus serves as astop and the spring insures the opening of the valve to admit thescavenging air to the blower when there is no high steam pressure in thebody 11. Since when the blower is operated, the steam pressure in theblower head may be up to six hundred pounds or more per square inch, Iso construct the device that this high pressure will not throw the valveto its seat with extreme violence. By making the parts as described andforming in the valve steam a plurality of longitudinal grooves orchannels 35 which extend entirely through the collar 32, I iind I canavoid the valve hitting its seat too hard when high pressure steam isadmitted to the head during the boiler blowing operation. As shown inthe drawings four equally spaced grooves having a depth and a width ofone-eighth. of an inch, extend from the end of the stem to a pointbeyond the collar 32 as seen in Fig. 2. The grooves 35 communicate Vmay.be used for other purposes and with various fluids with radial grooves35a which extend transversely across the end-of the stem 28 as seen inFig. 5. The purpose of the transverse grooves 35a is to enable the valve27 to be ground to its seat 26 by means of a screw driver or similarrotatable tool inserted into the neck 21 while theparts of the casingremain connected. The portion 28 of the stem has a diameter of nineteenthirty-seconds ofl an inch, while the radially slotted collar 32 has adiameter of twenty-nine thirty-seconds, the overall length of the valvemember being one and eleven thirty-seconds. The total cross-sectionalarea of the annular series of grooves in thestem portion 28 is greaterthan the crosssectional area of the three-eighth of an inch pipe l13 sothat there will be no back-pressure and the scavenging air will passfreely through the valve when it is opened by the spring 33. It wili benoted that the grooves 35 are relatively large so that the low pressureair will pass freely through the device, and that said groovessubstantially reduce the end area of the piston 28 exposed to the highpressure steam admitted into the device through the inlet 21, so thatthe valve is not driven against its seat 26 with damaging force. Byactual tests i have found that when the valve is so constructed, it willoperate efficiently on air pressure as low as a pound or less and steampressure up to six hundred pounds and at temperatures as high as 850 F.However when the valve is used in connection with low pressure boilershaving steam pressures of from one hundred to one hundred and ftypounds, I find the valve will operate more satisfactorily i'r` a Monelmetal ring 36 (Fig. 6) is placed on the stern portion 23 against theadjacent at face of the collar 32, as shown in Fig. 2. This flatcylindrical ring covers the slots or portions of the grooves 35 whichextend through the collar and hence the groove or slot area throughwhich the steam passes to act on the valve head is reduced. The use ofthe restricting ring 36 permits the same valve to be used in connectionnwith various steam pressures and renders unnecessary dinerent sizes ortypes of valves with openings of diierent areas through the collar.

It is believed the operation will be clear from the foregoing. Howeverit may be repeated that the relatively weak spring 33 will insure theopening of the valve when there is no high pressure in the blower head.Thus the scavenging air will pass through the valve at all tunes whenthe blower is not being used so that the corrosive gases of the furnacewill be kept out of the head and tne blower element. However when theblower 1s 1n operation the high steam pressure in the body 11 will acton the valve to close it, and there will be no leakage of steam if intothe air line and the, boiler room.

While the invention is espec1ally well adapted for use as a scavengingair line valve for soot blower heads, 1t

whether gaseous or liquid, and with various pressures. In some cases itmay be desirable to vary the tension of the valve opening spring. Thatmay be accompllshed by providing a longitudinally adjustable abutment 37for the spring on the stem between the head of the valve and the slottedcollar as shown in Fig. 7. Screw threads 38 are formed on the portion31a of the valve stem and the abutment 37 is in the form of a two-partinternally threaded collar or nut which is adjustable on the threads tovarythe tension of the spring 33a. The two sermcircular half sections ofthe nut 37 as seen in Fig. 8 are secured to each other by screws 39which when 'tightened hold the nut in its adjusted. position. The springabutment .nut or ring 37 has its edge formed with notches 49corresponding Vto the slots 35a in the collar 32a and stem portion 23ato permit the passage of air. 'It will be noted that the screw threads38 terminate shorthot the collar 32a so as to `form a stop to preventthe ring nut from closing the slots or openings in the collar. Sincethis modified form of the valve is otherwise the same `as the firstform, the same reference numerals with the exponent a have been used.

From the foregoing, taken in connection with the accompanying drawings,it will be seen that novel and advantageous provisions have been madefor carrying out the. objects of the invention, and while preferenceshave been disclosed, attention is invited to the possibility of makingvariations within the scope of the invention as claimed.

I claim:

l. An.y automatic check valve permitting low-pressure uid ilow in onedirection and automatically closing f against high-pressure fluid flowin the opposite direction,

comprising an elongated casing provided at one end thereof with meansadapted to connect the same with a source of low-pressure iluid andprovided at theother end thereof with means adapted to connect the samewith a high-pressure fluid receiver, said casing having a Huid passagetherethrough from end to end, said passage being enlarged intermediateits ends to provide a cylindrical valve chamber having an annular valveseat adjacent `the lowpressure end of said passage, a cylindrical guidechamber of less diameter than said valve chamber positioned coaxiallywith said valve seat and an annular, radially disposed, imperforate stopwall between said chambers, a valve assembly in the enlarged portion ofsaid passage including an annular valve head to engage said seat, acoaxial stem projecting from said head in the direction of thehigh-pressure end of said passage, an annular stop collar on said stemintermediate its ends and movable in said valve chamber for engagementwith said stop wall, said collar having its periphery in substantiallyslidable engagement with the inner wall of said valve chamber, acylindrical guide portion on the free end of said stem and slidablyengaged with the wall of said cylindrical chamber and an annular seriesof longitudinal grooves formed in the peripheral surface of thecylindrical end portion of the stem, said grooves also extendingentirely through said collar and outwardly through peripheral portionsof, the latter to permit high-pressure fluid entering said other end ofthe passage to expand in said valve chamber, a valve-opening coil springsurrounding a portion of said stem to move said collar against saidwall, said collar having .a at face opposed to said wall, and a flatcylindrical ring removably positioned on said cylindrical end portion ofthe stem between said at face and said wall to cover the portions ofsaid grooves in saidV collar which open through said flat face andthereby restrict the passage of the high-pressure fluid past sai-:i coar.

2. A scavenging air valve for soot blowers to give free ilow oflow-pressure air in one direction but to close to high-pressure steamilow in the opposite direction, comprising a casing having high-pressureand low-pressure inlets and between said inlets a cylindrical valvechamber and a cylindrical valve-guiding chamber concentri callydisposed, said valve-guiding chamber being of less diameter than thevalve chamber, said valve-guiding chamber having one end in opencommunication with said high-pressure inlet, there being an annular stopwall at the other .end of said valve-guiding chamber where itcommunicates with one end of said valve chamber, the other end of saidvalve chamber being in open communication with said low-pressure inletand having an annular valve seat concentric with said chambers, a valveassembly in said casing made of metal and in one piece, said assemblyhaving a stem with an integral disk at one end forming a valve head tocoact with said seat, with an integral elongated cylindrical piston atits other end of a diameter to slide in said valve-guiding chamberV tosupport and guide the valve assembly and with an integral annularVradially projecting collar at the juncture of the inner end of saidpiston with the stem, said collar being cylindrical and having adiameter slightly less than the diameter ofthe valve chamber and alsohaving one face in opposed relation to said stop wall and its other facein opposed relation to vsaid other end of the valve chamber, there beingin said valve assembly an annular series of longitudinal grooves whichextend throughout the length of said piston and into a portion of saidstem and which aline with and communicate with a corresponding seriesofradial slots in said collar, the total cross-sectional area of saidvgrooves being at least equal to the crosssectional area of saidlow-pressure inlet to allow'free tlow of low-pressure fluid through thecasing when the opening movement of the valve is stopped by theengagement of said collar with said stop wall, and a coil spring in thevalve chamber surrounding the valve disk and stern and thrusting at oneend against said collar and at its other end against said other end wallof the valve chamber.

3. A valve for the purpose Yset forth composed of a casing havingdetachably connected body and cap sectlons, a one-piece valve assemblyin said casing and a coil spring lto actuate the -valve assembly in onedirection, the body section-having a cylindrical valve chamber openingthrough one end with internal screw threads at said end, the other endof the body section having a low-pressure uid inlet with a valve seatconcentric with said chamber, the cap section having at one end externalscrew threads to engage said internal threads and also having acylindrical valve-guiding chamber concentric with and opening into saidvalve chamber, the extremity of said one end of the cap member formingan annular stop wall at the juncture of the two chambers, the other endof the cap member having a high-pressure uid inlet which opens into saidvalve-guiding chamber, said Valve assembly being formed of metal in onepiece and comprising a stern having at one end an integral disk forminga valve head to coact with said seat and having at its other end anintegral cylindrical piston of a diameter to slide in said valve-guidingchamber, said stem also having at the inner end of said piston acylindrical radially projecting collar with one face disposed in opposedrelation to said stop wall, said stem being further provided with anannular series of longitudinal grooves which extend from the end of saidpiston and past said collar, the latter having an annular series ofradial slots which register with said grooves, said collar also having adiameter slightly less than that of said valve chamber, the total crosssectional area of said grooves being at least equal to the crosssectional area of the low-pressure inlet to allow free i-low oflow-pressure fluid through the casing when the valve is open and saidcollar is engaged with said stop wall, said coil spring being disposedin said valve chamber around the valve head and a portion of the stem,and thrusting at one end against said collar and at its other endagainst said other end of the body section of the casing.

4. In a valve of the type permitting low-pressure uid flow in onedirection and automatically closing against high-pressure iluid flow inthe opposite direction; an elongated casing having a high-pressure inletat one end, a low-pressure inlet at its other end, a cylindrical valvechamber between said ends in communication with said low-pressure inlet,an annular valve seat in said chamber adjacent said low-pressure inlet,and a cylindrical valveguiding chamber coaxial with said seat and incommunication at one of its ends with said high-pressure inlet and atthe other of its ends with said valve chamber, said Valve-guidingchamber being of less diameter than said valve chamber, to provide anannular radially-disposed stop wall in said casing at the juncture ofthe two chambers, a valve assembly in said valve chamber including astem having at one of its ends a disk forming a valve head engageablewith said seat and at its other end a cylindrical piston slidable insaid valve-guiding chamber to support and guide the valve assembly, andan annular stop collar on said stern at its juncture with said piston,said collar being disposed in said valve chamber in opposition to saidstop wall and having its periphery slightly spaced from the wall of saidvalve chamber, the free end of said piston being at all times exposed touid pressure entering said high-pressure inlet, said piston having inits periphery an annular series of longitudinal grooves extending fromits free end and opening at all times into said valve chamber betweensaid valve disk and said collar, the latter having an annular series ofradial slots forming extensions of the grooves in said piston, saidgrooves reducing the end area of the piston and permitting high-pressurefluid to pass the piston end and expand in said slots and in the valvechamber in rear of said valve disk, said collar having a at face opposedto said Wall,

together with a flat cylindrical ring removably positioned on saidpiston between said at face and said wall to cover the portions of theslots in said collar which open through said Hat face and therebyrestrict the passage of the high pressure fluid past said collar, andspring means in said casing to urge said valve disk away from its seat.

5. ln a valve of the type permitting low-pressure fluid ilow in onedirection and automatically closing against high-pressure fluid ow inthe opposite direction; an elongated casing having a high-pressure inletat one end, a low-pressure inlet at its other end, a cylindrical valvechamber between said ends in communication with said low-pressure inlet,an annular valve seat in said chamber adjacent said low-pressure inlet,and a cylindrical valveguiding chamber coaxial with said seat and incommunication at one of its ends with said high-pressure inlet and atthe other of its ends with said valve chamber, said valve-guidingchamber being of less diameter than said valve chamber to provide anannular radially-disposed stop wall in said casing at the juncture ofthe two chambers, a valve assembly in said valve chamber including astem having at one of its ends a disk forming a valve head engageablewith said seat and at its other end a cylindrical piston slidable insaid Valve-guiding chamber to support and guide the valve assembl and anannular stop collar on said stem at its juncture with said piston, saidcollar being disposed in said valve chamber in opposition to said stopwall and having its periphery slightly spaced from the wall of saidvalve chamber, the free end of said piston being at all times exposed tofluid pressure entering said high-pressure inlet, said piston having inits periphery an annular series of longitudinal grooves extending fromits free end and opening at all times into said valve chamber betweensaid valve disk and said collar, the latter having an annular series ofradial slots forming extensions of the grooves in said piston, saidgrooves reducing the end area of the piston and permitting high-pressure:Huid to pass the piston tend and expand in said slots and in the valvechamber in rear of said valve disk, and spring means in said casing tourge said valve disk away from its seat, said spring means includes acoil spring surrounding said stem and thrusting at one end against theadjacent end of said valve chamber, said stem being externally screwthreaded between said Valve disk and said collar, and an adjustableabutment against which the other end of said spring thrusts to move saidvalve disk away from its seat, said abutment including an internallyscrew threaded collar engaged with said screw threads and composed oftwo abutted semi-circular half sections and screw threaded fasteningsclamping said sections together on the threaded portion of said stem.

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